Synthesis of novel (Cr, Cu)-doped BiFeO₃ perovskite as a photocatalyst for Rhodamine B degradation under sunlight irradiation

This study investigates the synthesis of (Cr, Cu)-doped BiFeO₃ perovskites with compositions BiFe_1-x(Cu_x/2Cr_x/2)O₃ (x = 0, 0.1, and 0.2) using the sol–gel method, calcined at 850 °C, to enhance their structural and photocatalytic properties. A comprehensive suite of characterization techniques, including X-ray diffraction (XRD), Rietveld refinement, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and UV–vis spectroscopy, was employed to analyze the synthesized materials. XRD patterns and Rietveld refinement revealed a phase transformation from BiFeO₃ to Bi₂Fe₄O₉ with increasing Cr and Cu doping levels. SEM analysis showed variations in microstructure, with the average particle size decreasing as Cr and Cu doping increased, reaching a minimum value of 2.355 μm at x = 0.2. The band gap measurements confirmed the successful incorporation of Cr and Cu into the BFO lattice, resulting in a reduced band gap of 2.04 eV at x = 0.2. Photocatalytic performance was assessed by the degradation of Rhodamine B (RhB) under sunlight irradiation. The sample with x = 0.2 demonstrated an impressive 98% degradation efficiency within 180 min, with a calculated rate constant of k_app = 0.01535 ± 0.00122 min⁻¹. This work highlights the potential of (Cr, Cu)-doped BFO perovskites as efficient photocatalysts for environmental remediation applications.